In a widely used bookbinding apparatus for producing a booklet, image-recorded sheets are stacked to form a sheet bundle and the spine of this sheet bundle is applied with hot metal type adhesive, whereby binding operation is performed.
The adhesive applied on the spine of the sheet bundle is a solid mass at the normal temperature. A predetermined amount of adhesive is put into the hopper of the apparatus.
A proper amount of the solid adhesive in the hopper is fed to a melting tank as s storage member at a predetermined time interval. It is melted in a melting tank provided with a heater, and is kept at a preset temperature. The adhesive kept at the preset temperature is applied on the spine of the sheet bundle by a gluing device.
When continuous bookbinding is to be performed, the adhesive stored in the melting tank is preferably kept at the optimum preset temperature.
However, when a non-bookbinding mode continues for a long time, unwanted power consumption, deterioration of the adhesive or generation of offensive smell from the adhesive may result if the adhesive stored in the melting tank is kept at the optimum preset temperature.
Such a problem fails to meet the requirements of an office wherein greater importance is placed on energy saving, cost reduction and maintenance of a comfortable working environment.
In a bookbinding apparatus for solving the problem disclosed in the Unexamined Japanese Patent Application Publication No. 2007-57580, the heater is turned off upon termination of bookbinding operation, or the temperature is reduced to a level lower than the optimum preset temperature.
However, when the heater is turned off, the room temperature is reduced. Thus, the adhesive having been liquefied is again turned into a solid.
Thus, when gluing is performed, the adhesive in the solid state must be heated to the temperature wherein gluing is possible. This will consume a lot of time.
When switching the temperature to the level lower than the gluing temperature without turning off the heater, the time required for resetting is prolonged if the switching temperature is too low,
If an application roller in contact with the adhesive is rotated before the solid adhesive is liquefied, the drive mechanism or drive circuit of the application roller may be damaged.